Valve grinding machine



July 4, 1933. B. T. STEBER VALVE GRINDING MACHINE Filed Jan. 22, 1929 4Sheets-Sheet 1 fijww I 525153 ATTORNEYS July 4, 1933. B. 1". STEB'ERVALVE GRINDING MACHINE Filed Jan. 22, 1929 4 Sheets-Sheet 2\\\\\\\\\\\'\\\\\\\\\\WWis ATTORNEY 5 y 4, 1933- B. T. STEBER 1,916,775

VALVE GR INDING MACHINE Filed Jan. 22, 1929 4 Sheets-Sheet 3 a W 50 a 44I fi U 03 .57 56 w. v

III

ATTORNEY July 4, 1933. 8. T. STEBER 1,916,775

VALVE GRINDING MACHINE Filed Jan. 22, 1929 4 Sheets-Sheet 4 ATTORNEY lPatented July 4, 1933 PATENT OFFICE 7 BERNARD T. STEBER, OF UTICA, NEWYORK v 'VALVE GRINDIN G MACHINE Application filed January 22, 1929.Seria1:N0. 334,251/

This invention relates to machinesfor grinding valves.

The purpose of my present invention is toprovide a new and improved formof ma 5 chine'for grinding valves and particularly toprovide a machinewhich is especially adaptedto readily and accurately grind valvesespecially valves such as are common- 1y known as poppet valves orpuppet valves,

Further purposes of the invention are to provide a machine of the classdescribed which is simple and economical in co'nstruction, easilyoperated, compact in size and moderate in weight, readily adapted to beoperated by hand or by power with a minimum of power in either case andfurther a machine which is adapted to be easily set to grind valves ofdifferent sizes or valves where the face to be ground may be at an angleof ninety degrees to the axis of the valve or where said face is at adifferent angle such as the common bevel faced valve; and fur-' ther toprovide a machine having a new and improved form of advancing the'valvetwards and withdrawing it from the grinding face by eans of a swingingcradle which allows the valve carried thereby to be swung forwardly pastor over the grinding face and transversely of said grindingface andtransversely thereof again which swingng motion carrying the valvetransversely of V the grinding face causes an accurate and even grindingof the valve with a minimum of power consumption; a further purpose isto provide in'a machine of the form disclosed simple means to rotatethevalve while it is being ground'and also to provide means to adjustthe position of the valve relative to the plane of the grinding wheelface so that the machine may be adapted to use with a large variety ofkinds and sizes of valves and also readily adjusted, successively ifneed be, to positionsito grind as much or as little from the valveasrequired.

Further purposes are to provide in a machine of the] sort describedmeans for so swinging the cradle past the'abra'sive wheel which meansmay be operated by hand where separate. power :is used to drive theabrasive then back past the grinding face, that is wheel or may beoperated by the same means as actuates the abrasive wheel when that'ishand operated so that in a hand operated machine'the operators two handscan effect the three movements necessary to properly operate themachine; I'further provide incertain forms of the machine co-operativeconnection between the means for driving the abrasive wheel and themeans for advancing and withdrawing the valve past the wheel so thatthese two movements may be effected from'one hand-movedmember or fromone motor or driven member. 7 f

Fig. 1 isa plan view of a valve grinding machine e'mbodyingthisinvention with theparts shown in the position they occupy when the valveis'out of engagement with the grinding wheel.

Fig. 2 is a front elevation of the machine that is looking directly atthe end' of the shaft 23 carrying the smallcam wheel. V Fig. 3 is avertical sectional view on line; 33 of Fig.1 looking in the directionindicated by the arrow.

Fig. 4 is a vertical sectional view online 44 of Fig.1; I

Fig. 5 is a front elevation" of a modified form of the invention.

Fig. 6 is a plan view of anotherform of the invention and Fig. 7 is'asectional view so} on line 7 7 of Fig. 6.

Referring to the drawings in amore particular description and firsttothe form shown in F igs. 1 to it will be seen that the'machine'comprises a frame 10 and'an abrasive wheel 11 revolubly mounted thereon,a cradle 12 v v swingingly mounted upon the frame so as to swing thevalve holder generally denoted by the reference numeral 13'a11d thevalve 14' carried thereby so that the face of the valve to be ground maybe carried-forward into; engagement with and past the abrasive'wheel andthen back past said wheel and soout of engagement with the grinding face1 5 of the abrasive wheel. Means hereinafter described in detail areprovidedto'automatically or independently thus swing the valveboldervand the valve carried thereby towards and away from the grinding wheelthat is past and re-past the grinding wheel'as'the grinding wheel isrotated. Independent means are provided for meanwhile rotating the valve14 by rotating the valve spindle 16 by means of which the valve isrotatably held in the valve holder 13.

The frame 10 of the machine is adapted to be readily but removablysecured to the edge of a bench or solid table 17 as by the bed plateportion 18 of the frame resting against the top of said bench and beingheld thereto by a depending bracket '19 and clamping screw 20 havinghand wheel 21. In the upstanding portion of the frame are bearings 2222carrying the shaft 23 upon which to the rear of the frame and over thebed plate portion 18 is mounted the said grinding wheel 11. Upon thegrinding wheel shaft 23- is provided a small-gear 24 meshing within thecasing 25 with'the large gear'wheel 26 mounted on shaft 27 carried insaid casing and frame. When the machineis to be hand operated it will beprovidedas shown in full lines in Figs. 1 and 2 with an operating crankmachine may be bodily set up. in other posi-.

tions upon the bench or other fixed member. Upon the frame of themachi-near-e' provided two upstanding ears 30 and31 spaced apart andhaving mounted therein the opposite ends of the shaft 32 upon which. isr-ockingly or swingingly carried the cradle 12 'as particularly shown inFigs, 1 and 4;. The shaft 32 is parallel with the axis of the cup-shaped grinding wheel and spaced therefrom and spaced therebelow farenough so that the valve spindle 16 carried in the valve holder 13 willpreferably be about on the same hori zontal plane as the axis of thegrinding wheel. The cradle 12 comprises a platform 33 from which dependtwo spaced ears 34c and 35 which are mounted-upon the shaft 32 as bysaid-ears having holes to litsaid shaft; The cradle 12 is adjustablelongitudinally of the shaft 32 by meansof oppositely disposed adjustingscrews 36 and 37, said screw 36 being mounted in the ear 30 and extending inwardly into'conta-ct with the car 34 on the cradle and said screw37 pr jecting through upstanding ear 31 on the frame inwardly againstthedepending ear 35 on the cradle. By loosening one of these set screwsand tightening up the other the cradle may ob-.

viously beadjusted to the desired extent relative to the shaft 82 whichadjustment will as.

particularly seen in Fig. 1 elfect an adjust- V ment of the face of thevalve 14: towards or from the vertical plane of the'grinding face 15 ofthe grinding wheel so as to grind more or less deeply as desired. V Thevalve holder generally denoted by the numeral. 13 is adjustably mountedupon the cradle 12 so as to swivel. or pivot'upon the pivot. screw 38connecting the valve holder and the cradle at the forward end of thevalve holder and nearithe edge of the-cradle towardsthe grindii'lgwheel. The platform 33 of the cradle is provided with an integral orsecurely fixed extension on its side away from the grinding wheel andthrough the platform and particularly this extension thereof is pro*ided with an arc-shaped slot 39 having its center at the axis of thescrew 38. A screw ll) extends through the arcslot in the platform 33 ofthe cradle and tliroiiigh a hole or slot in the floorll. of;

the valve holder and receives a nut l2where; by the valve holder may beset at desired angle relative to the cradle. The rangeof such adjustmentwill. preferably be from a position such as shown in Fig. 1 wheretheaxis of the valve stem 16 is about at an angle of .l5 with the verticalplane. of the shaft 32 carrying the cradle to a position where the axisof the said spindle will be parallel to the said shaft. WVhen the partsare set to the position as shown in 1 the machine is adapted to grind orre-surface valves having a bevel face such asshown on thevalve 14:

in Figs. 1 to l.

Vi hen. the valve holder is loosened from theposition shown infFig. 1and swung substantially over the platform of thecradleso as to have thespindle 16 parallel with-the cradle shaft the machine will be adapted togrind a valve having a face at right angles with V-shape'd bearings 45-and 4.6 respective-. lv. Into these l -shaped bearings is placed.

the spindle 16 of the valve to be groundavith said valve 1% beyond orforward of the front end 4-3 andfront bearing 45 The spindle 16 7 1Srotatablv but readily removably mounted or held against'saidV-shapedcbearings by two spacedswinging-leaves 47 hingedly or ivotallymounted. at their lower ends upon" the valve holder floor 4:1.and'bearmg inter mediate their length against thespind'le-and providedabove-the line of the-spindletwith liZO swingingly mounted rods 48reaching over the spindle and having their forward ends screwthreadedand dropped into slots 49 provided in the front plate 50 extendingvertically of the valve holder from its front and rear ends43 and 44. Onthe .outer or screw-threaded ends of each ofsaid rods are mounted twospaced knurled-edged nuts 51 z and 52 inside and outside respectively ofthe front plate.

on the rods 48 determines the extent to which front plate 50. Byloosening the outer nuts the rods may be lifted from the slots 49 andthe leaves may be drawn against the, valve spindle so as to allow thespindle to be held loosely enough to be readily rotated but at the sametimetight enough to allow of the work being done very accurately. Itwill be understood that the specific form of bearing for the spindle andthe specific form of'means for readily and removably mounting andholding the spindle of the valve in the valve holder are simplyillustrative of means for so revolubly but removably mounting thevalvespindle in the valve holder and are not.

limitations of my invention.

As very simple but effective means for rotating the valve in its holderI provide and attach to the rear or projectingend of the spindle 16 aremovable dog 53 like a lathe dog having in one end of the shank 54thereof an eye 55 large enough to receive any valve spindle. The dog isremovably but securely held'to the spindle by headed set screw 56. thedog is bent at right angles away from I the valve holder forming ahandle 57 adapted to be grasped and turned by the left hand of theoperator whereby all parts of the face of the valve are successivelybrought into engagement with the grinding face of the abrasive wheel.When a valve has been sufficiently re-surfaced the dog is removed fromthe spindle of that valve andplaced upon the spindle of the next valveto be ground or placed withthe machine readyfor any subsequentoperation. I

' The valve is heldfrom longitudinal move ment in the valve holder bythe flat or top head of the valve being engaged by an arm 58 which ispreferably setor so spaced as to hold the lower or opposite face/59 ofthe valve hub 60 against the outer or forward side of the outer end orblock 43 near'the V-shaped bearing 45. The arm 58 is a part of a strongL-shaped bracket the other part or base 61' of which is at right anglesthereto and adjustably secured to the outer "or The outer end of theshank of forward'side of the front plate '50 of the valve holder. Thebase 61 may be conveniently held in adjustable relation to the frontplate 50 by means of a short post 62 enlarged at its forward end to forma hand wheel preferably having a knurled edge. At its inner end the post62 is reduced in diameter and such reduced diameteredpart 64 is"screw-threaded to engage the screw-thread ed hole in the front plate 50of the valve holder through a longitudinally extending slot 65 providedin the base 61- of said bracket. The shoulder at the inner end of post62 is thus brought into holding engagement with the base 61. f Thisbracket may be adjusted so as to locate the holding arm'58 thereof at aproper distance from the opposing outer face of the end 43 of'the valveholder to adapt the machine for use with various sizes or forms ofvalves.

Under some circumstances it is an advantage to j have a'supplemental orfurther means for adjusting the face of the valve to be ground relativeto the plane of the grinding wheel in addition to the means alreadydescribed for adjustingthe cradle longitudinally of its shaft. Suchadditional or supplemental adjusting meansIpreferably' provide the formof a bed plate 66, normally fixedly secured to the bottom of the floor41 of the valve holder 13. This bed plate accordingly forms the realbottom of the valve holder and rests directly upon the platform 33 ofthecradle. This bed plate is the part of the valve holder which isdirectly swiveledor pivoted to the cradle by the" swivel or pivot pin orscrew 38 already ,described. -This bed plate 66 is preferably of aboutthe same width as the floor 41 of the holder but a little-dongerespecially at thev forward inner corner to provide for the said pivotscrew 38. The floor 41 is adjustable longitudinally of the bed plate 66and these parts are held in desired adjusted position longitudinally ofeach other as by means of short screw threaded posts 67 upstanding fromthe bed plate through elongated slots 68in thelfloor and engaged abovethe floor by nuts .69. To accommodate this longitudinal adjustmentbetween the main part of the holder and its bed platethe hole in thefloor 41 through which passesthe'screw 40 coming up through the arc-shaped slot 39 in theplatform 33 of the cradleis made as a slot 70.WVhen this 'adju'stment'of the upper part of the valveholder 13-relativeto its bedplate 66 is to be made itwill be understoodthat the nut 42 onsaidscrew'40 has to be loosened. After such longitudinal adjustment iseffected the nut and screw 40 are again tightened so as to hold'thevalve holder 13 bodiiy at i'tsjdesired angle relative to the cradle 12.

In the machine shown Figs'el to 4 means are provided for automaticallyswinging the cradle so as'to move the valve face transverseone or which.is rotated by handby the p-v era'tor grasping the handle29 on the crank28. The meansfor so automatically swinging the cradle and therewiththeyalve by means co-operatively connected to the means for driving theabrasive wheel, will now be described. p

The cradle 12 has securely butadjustably secured to the outside of .itsforward ear an upstanding arm 71.. A convenient form of such adjustableconnection is by means of a center screw 72 connecting said arm and earand one or more side screws 73 passing through slots in the arm intoscrew-threaded holes in said ear. This arm 71 extends upwardlyconsiderably past the top of the valve in the holder and intermediateits length the arm is provided with a forwardly projecting pin 74-. Thispin engages the left hand periphery of a double involute cam disk 5mounted upon stub shaft 76 projecting forwardly from an upstandingbranch 77 of the frame. This branch of the frame may be convenientlyformed as a strong strap secured to the front of the casing 25 enclosingthe large and small gears 26 and 24 already mentioned. To, the left ofthe bottom of the said frame member 77 thereis pivotally secured to thecasing 25 as by pivot screw 7 8 a lever 79 having a forwardly projectingpin 80 which engages the right hand side of the periphery of the camdisk about opposite the shaft/T6. The said lever 'l'9is mounted in thesame vertical plane. as the frame branch illellllJQI T? so that thelever .79 passes upwardly just to the rearof the cam disk 75 as theparts are seen'in Fig.2. The lever 79 extends above the said pin andpreferably to a point above thecam disk 75 and at its upper end hasattached thereto the right hand end of contractile spring 81 the otherleft hand end of which, is attached to end of ar1n71 projecting upifromthe upper the cradle. v

It will now be seen that as the cam disk 7 5 is rotated the cam facethereof will press pin 80 to theright hand side as seen in Fig. 2 andthereby the lever'TS towards the right. This movement towards the rightof lever 79 will be communicated through spring 81 to cause asubstantially similar movement in arm 71 fixed upon thecradle 12carrying the va-lve holder 13 and thereby swing the valve tran verselyacross the grinding face 15 of the abrasive Wheel 11 until the high spotof said cam wheel is opposite the cam pin SO. when the valve willpreferably bejust past the inner edge of the grindingface v1 5, thatis'80 on lever through the spring 81 to cause a yleldlng drawing duringtheadvancing movement of movement it-will be noted is a positive one due tothe positive connection of the periphery of the cam disk 75 with the campin 74 on the arm 71 rigidly attached to the cradle. Qnthe otherhand theforward or advancing movement of the cradle is preferably ,as

shown in the construction illustrated a spring tensioned or yieldinglytensioned movement due to the cam disk 75 engaging the cam pin 79' whichmotion is transmitted thejcradle. This yielding advancing movementallows the cradle to hang back alittle to take the grinding upon thevalve in a sloweradvance in case a valve has been set or'themachineadjusted so asto have the face 14 of the valve too far past theplane of the grinding face 15 of the grinding wheel. If the excess ofcut is small the machine in one or two movements will equalize thegrinding upon the valve. If the excess of cut is too great the operatorcan at once manually withdraw the'cradle and valve holder bodily bygrasping the valve holder and pulling it to the left against the tensionof the spring 81. The operator can then operate the machine untilthelever 'TE) is moved to the left whereupon the operatofs'hand can bereleased from the valve holderand with the parts of the machine in theposition shown in Figs. 1 and 2 the valve or more particularly the valveholder or the'cradle can be more accuratelyadjusted so as not to requiretoo muchto beground off of the valve at its first engagementwith thegrinding wheel. In various other conditionsalso it is an advantage to beable to manually swing the carriage back so asto disengage the valvefrom the wheel without having to stop to move the parts of the machineto produce this movement. o e

-As convenient but simple illustrative means for automatically causingthe swinging of the cradle in the necessary slow moveward ofth e camdisk 7 5 and secured to said cam disk so that rotation of the ratchetwheel 82 willcause rotation of the disk 75; A step.

by step movement is givento the ratchet wheelc82 and thereby tothe camdisk 7 5 in of the ratchet wheel and pivoted intermedi-' ate its lengthon pinSl secured to lever 8,5 which hasits lower end loosely mountedupon the said shaft 7 6 forward of the ratchet wheel 82. A back andforth movement isgiven to the pawl 83 by the outer end of the saidilever85 being swung back and forth'by a link 86 pivotally connected totheupper end of said arm 85. The other and lower end of said link 86 is inturn pivotally connected to the free end ofthe'lever 87 which has itslower end pivotally mounted on a short stub-shaft part of an electricmotor 94 which by a flexible joint such as 95 may be connected to the Inthis modification of course the V 88 projecting forwardly from thecasing-.25.

The lever 87 is provided intermediate its length with a cam pin 89 whichis engaged by the periphery of a cam wheel 90 mounted on shaft 27 androtatin therewith as by said cam wheel being fastenedv to the crank 28carrying the handle 29 as by screw 91 passing throughsaid crank into thesaid cam wheel. Cam pin 89 is' yieldingly pressed against cam wheel 90at all positions of the cam wheel by a coiled spring 89 stretchedbetween lever 89 and an adjacent projection provided on the casing 25.It will now be seenthat each revolution of the shaft 27 willmove thehigh spot of the cam wheel 90 past the'cam pin 89 and thereby impart aswinging motion to the lever 87 which is communicated through link 86back to'lever 85 causing advancement of the ratchet wheel one or twonotches-ac cording to the number of teeth upon the ratchet wheel and theextent of motion of the lever 85. As the machine is illustrated,

each swinging motion of the arm 85 advances the ratchet wheel 82 onenotch. WVith twenty teeth upon the ratchet wheel 82 it will be' seenthat twenty revolutions of the shaft 27 are required tomove the cam disk75 onejcomplete revolutionthereby causing one complete travel of thecradle'namelyan advance movement and a retractingmoves '1'nent.- It willbe obvious thattheratio of movement between the shaft 27 and the cradlemay be varied but the ratio suggested is foundto'be practicable. 'Asmall spring-92 attached to the free upper endof the pivot pawl 83 hasits upper. end attached to the lever 85 so as to yieldinglyholdfthelower end of said pawl in'engagemen't with: the teeth of theratchet wheel'82. The frictional grasping of the cam disk 7 5 betweenthe 'two cam pins 74 and due to the spring 81 "is sufficient to-holdthe: cam disk from moving backward when the pawl 83 is being swungbackward by lever 85.

In order to aid in securing greater accuracy in grinding the valves Iprovide means for constantly keeping the abrasive wheelas far from theface of the valve to be ground-as allowed by the bearings carrying theshaft 23 of said grinding wheel. As convenient means for doing this Iprovide the machine with aspring-tensioned arm 93 having its freeendbear upon the forwardend of the shaft 23 and its other end supported insuit able manner at the-'front'of the casing 25.

Preferably, this spring tensioned arm may subject-matter of a separatepending application heretofore made by me.

shaft 23.

In dotted lineson Fig. 1 there isshown a 3 handle 29 and hand-operatingcrank may be removed as the power motor 94 will directly drive at therequired high speed the abrasive wheelll and thepower will betransferred in reverse direction through the small gear wheel 24 to thelarge gear wheel 26 to cause through cam wheel 90 the required slowmovement of the cam disk 75 by the co-operative connections alreadydescribed between said cam disk 7'5 and the'cam' wheel 90. i Themodification of myinvention shown in Fig ,5 consists in entirelyeliminating any operative connection betweenthe means for rotating theabrasive wheel' and the valve carrier and cradle and in providingseparate manually operated means for directly swinging the cradle. Inthis construction a cupshaped abrasive wheel llha'ving' a verticallyarranged grinding face 15 as already described is utilized and thisabrasive wheel is rotated by power as by'a motor 96. I The abrasivewheel 15 is carried by suitable bearings provided on a frame-97lwhich isshown as adapted to be detachably secured to the edge bench or tableasby having its bedplate F18 held to the benchby a screw-threaded clampextendingthrough a depending bracket 19. The cradle 12 has its platformrockingly mounted relative to the bed plate 18 -as by the depending earsof said platform 33 being mounted on shaft 32'secured above said bedplate. "The cradle 12 and the valve holder is then constructed and usedexactly as heretofore described with regard to the formshown in Figs. 1to 4 except that in place of the short.

arm 71 a longer arm 98 is secured to the'outside of the forward ear 34of the cradle 12 and this arm projects considerably above the valveholder carriedby the cradle and isat its upper end provided with ahandle 99. By manually swinging this arm 98 by the operators right handupon the handle 99 the cradle and therewith the valve holder and thevalve thereon may beswung upon the axis of the cradle shaft 32 so as toadvance the face 14 of the valve to be ground towards and straightacross'the vertical grinding face 15 of the abrasive wheel and thenbackagain by -a reverse or backward movement of the said hand-operated arm98. It will be understood .of course that during this direct swinging orreciprocationof the cradle by movement of the lever 98 theoperator willbe rotating the valve at thedesired speed by turning the dog .53attached to the spindle of the valve. cradle and therewith the valvewill be thus The swung backward and forward as many times as needed to.bring the valve to the pro-per condition. If after a series of suchengagements of the valve with the abrasive wheel there are still dull orunground spots upon the face of the valve, the cradle will be movedlongitudinally of its shaft 32 by advancing these-t screw 36 as alreadydescribed. The

valve will be removed from the valve holder in the same manner asalready described and the valve holder may be ad usted on the cradle togrind the valve at the desired angle.

In Figs. 6 and 7 is shown a still further modified form of my invention.A valve holder as already described and a cradle substantially asheretofore described are utilized but the parts are so arranged andcombined that the swinging ofthe .valve by swinging or rocking movementof the cradle and the valve holder instead of advancingthe face of thevalve to be ground transversely across the grinding face of the wheel,advances the said face ofthe valve to be ground towards the abrasivewheel by movement in the plane.

of .the abrasive wheel.

. Flg. 6 1s a planvlew of a machine embodyin thls invention and Fi 7 isa vertical sectional view thereof on line 7 7 of Fig. 6.

In this form of the invention an abrasive wheel 1000f the common thindisk type is used providing a grinding face at its external periphery101 and this abrasive wheel is mounted in. suitable bearings and drivenby power as by a motor 102. The valve holder in this form is constructedpreferably exactly.

as already described soasto removably carry therein a valve by means ofits spindle with the device so as to provide upstanding cars 30 and 31carrying the cradle shaft 32 upon which, is rockinglv supported themovable part of the, cradle as by the ears 34 and 35 depending from thecradle platform 33 being mounted upon said cradle shaft. 32. From theplatform 33 there projects for- V wardly towards the axis of theabrasive wheel 100 and to theleft of the abrasive wheel; as V the partsare seen in Fig. 6 an extension 104 having an are-shaped slot 105..Upon'the platform of the cradle is mounted a. valve holder of the sameform'as already described in detail, with said valve holder having itsbed plate 66 pivotally mounted upon the platform 33- of the cradle asupon pivot screw 110 located towards the right hand end of the cradle astheparts are seen in Fig. 6. 7 With this swiveling connection betweenthe valve holder and the? cradle the valve holder may be moved from theposition shown-in Fig. 6 nearer to or fartherfrom the plane oftheabrasive wheel if the bevel'face of the valve is to be ground to adifierent angle or the valve holder may be swung so that the valvespindle will be parallel withthe plane of the abrasive wheel so that thedevice may be used to grind valves having a seat parallel'with the plane'4 of the disk of the valve. In this formof the invention the cradle andtherewith the valve holder and valve thereon will be swung. towards andupon the grinding face of the wheel by means of thehand lever 106project,

ing upwardly from the right hand, end of the cradle. Conveniently; thisleve'r:1;06.-will be secured to the right hand car 35 of the cradle.Means will be provided to stop the swinging movementof the valve towardthe abrasive wheel at the desired point and this stop. mechanism will beadjustable so as to allow. for limiting very accurately and by verysmall steps the extent to which the-valvemay be pushed towards thegrindingfacel Such adjustable stop mech-anism may conveniently be formedby the hand lever 106 having a rigid car 107; "projecting over therigid'part 108 of the machine immediately below the bottom of said lever106 with theear 107 provided with a slot through which extends the shankof a'cap screw 109, the lower end of which is .inf'screw-th-readedadjustable ens gagementwith the member;108 while the head 7 of theeap'screw engagesthe upper part of the ear 107 By loosening the said capscrew' the lever 106 may be moved farther towards the right as seen inFig. 7 whichwill result in carrying the face of the valve to be groundfarthertowards the grinding face 101 of the abrasive wheel.

.What I claim as, new and desire to secure.

by Letters Patentis: 1. In a machine frame, a drive shaft,'meansoperated by said drive shaft for rotating said wheely'a cradle mountedto oscillate on said frame about an axis parallel tothe axis ofrotationofsaid wheel, a, valve holderadjustable on said cradie, a stubshaft onsaidframe,a double involute cam mounted to rotate'on. said stubshaft, a post fixed. toone end of said cradle and having a pinextendinglaterally there from in sliding contact withv the edge of saidfor grinding valves a frame, an abrasive wheel. rotatable on said cam, alever pivoted at oneend to said frame and having a pin extendinglaterally therefrom in sliding contact With the edge of said cam, saidpost and lever being arranged so thatthe pins thereon contact With theedge of said cam at substantially diametrically opposite points, aspring connecting the free ends of said post and lever to hold said pinsin yielding contact With the edge of said cam, a ratchet fixed to saidcam, a first link having one end pivoted to said stub shaft, a

pawl pivoted to said link and cooperating drive shaft for rotating saidWheel, a cradle mounted to oscillate on said frame about an' axisparallel to the axis of rotation of said Wheel, a valve holderadjustable on said cradle, a stub shaft on said frame, a double involutecam mounted to rotate on said stub shaft, a post fixed to one end ofsaid cradle and having apin extending laterally therefromin slidingcontact with the edge of said cam, alev'er pivoted at one end to saidframe and having a pin extending laterally therefrom in sliding contactWith the edge of said cam, said post and lever being arranged so thatthe pins thereon contact With the edge of said cam at substantiallydiametrically 0p- 1 posite points, a spring connecting the free ends ofsaid post and lever to hold said pins in yielding contact with the edgeof said cam,

and mechanism connecting the drive shaft to said cam to rotate the camat a rate of rotation lower than that of the drive shaft.

In witness whereof I have aflixed my signature, this 12thday of January,1929.

BERNARD T. STEBER.

